1. Field of the Invention
The invention relates to a method and apparatus for determining the foaming characteristics of crude oil.
2. Background of the Invention
The foaming characteristics of crude oil streams produced from a well are important in designing apparatus for separating the crude oil stream into oil and gas. The most common method of separating oil and gas produced from a well is to pass the oil and gas mixture under an initial high pressure into a vessel under reduced pressure wherein the gases dissolved in the oil flash off the oil and the heavier oil separates from the gas by gravity. The volume of the vessel and the retention time of the oil are sufficient to allow the oil to accumulate and to be withdrawn from the bottom portion of the vessel with the separated gas being withdrawn from the top portion of the vessel. As gas separates from the oil, foam accumulates on the top of the oil and the amount of foam formed will vary depending upon the characteristics of the crude oil being produced. Therefore, the capacity of the vessel must be sufficient to accommodate the volume of foam formed in the vessel based upon the foaming characteristics of the crude oil and crude oil production.
Presently, the foaming characteristics of oil are measured by bubbling a gas through a sparger tip into a given volume of oil, contained in some suitable measuring vessel. This practice is unsatisfactory because the character of the sparger tip may change over a period of usage and resulting foams are not properly comparable. Furthermore, the bubbles of foam formed with sparger systems are usually larger than those which result from the self-nucleation of foam by decreasing the pressure on a gas-saturated liquid, i.e., when the gas is "flashed" from the liquid.
The present invention provides an improved method for measuring the foaming characteristics of crude oil utilizing a gas-oil saturator and a flash separator comprising a transparent elongated horizontal cylinder.